Armor-plate.



PATENTED JULY 24, 1906.

E. GATHMANNQ ARMOR PLATE.

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EMIL GATHMANN, OF BETHLEHEM, PENNSYLVAIUA, Assienon or ONE-FOURTH To LoUIs GATHMANDLIOF WASHINGTON, DISTRICT.

OF COLUMBIA.

ARMOR-PLATEF.

Patented Jul 24,1906.

Application filed July 2,1904. Serial No..215,156

' Plates, of which the following is a-specification.

My invention has for its object the production of an armor-plate designed to afford the maximum strength with minimum wei ht.

Armor-plates are usually face-har ened, and their resistance to penetration is proportioned to the thickness of the plate and the hardness of its face. A homogeneous steel plate-i. 6., one which is not face-hardened is easily penetrated by a hard'projectile, and

the penetration is effected by the compression of the molecules of the metal on lines approximately at right angles to the line of penetration. In a face-hardened plate, on the contrary, the metal does not ield by the compression of its molecules; ut-penetration is effected by a punching action of the projectile. The nose of the projectile, acting as a punch, breaks through the hardened sur-, face, carrying a portion of the metal with it in the form of a button, which is punched or sheared out of the hardened face of the plate and is driven into the soft portion of the plate or through it, resulting usually in the breaking of the plate after the penetration has proceeded beyond the hardened portion, and the splitting action thus permits the button to escape. The power of the plate to resist penetration by a projectile can be increased indefinitely by adding to the thickness of the plate, and of course the weight of the plate increases as its thickness is increased. The power of the plate to resist displacement of its particles by punching with a theoretically-unyielding projectile of a given caliber can be established in terms of the p'rojectiles circumference, and the thickness ofthe plate can likewise be estimated on approximately the same circumferential line. It follows, therefore, that the plate should be thickest at lines corresponding to the crosssection of a projectile of the smallest caliber capable of penetrating armor upon normal impact. It follows, further, that within this cross-sectional area the plate may be thinner. Proceeding in accordance with'these proposi tions I have devised an armor-plate calcu.

lated to afford a higher percentage of resistance in pro ortion to the weight than has been hereto ore attained. I accomplish this i lesult'by deforming the body of the plate, so as to increase its effective thickness and consequent resistance to penetration without increasing the wei ht of the plate. I aceomplish this object y deforming the surface of the plate onone orboth sides, but referably on its face side only. These de ormations have preferably a series of de ressions of uniform de th and cross-section ounded by ribs of unif ribs'intersecting'each other, so as to define orm heightandcross-section, the

the depressions and the ribs being produced in any convenient way, as by drawmg, punch ing, or rolling.

. By means of my invention I am able to increase the efficiency inthe resisting power of I out any addition to its weight.

In the accompanying drawings I have repsented for purposes of illustrationonly two forms of plate, which Will serveto indicate how my invention may be practically carried out.

In said drawings, Figure 1 is a face or plan 'the plate at least twenty-five per cent. with* view of a' plate, one portion of which has been deformedso as to roduce thealternate ribs and depressions; ig. 1, a perspective view of a portion of a plate. Flg. '2 is a. longitudinal sectional elevation 'ofthe plate on the line 2 2 of Fig. 1. Figs. 3 and 4 are similar both faces. I I

In the drawings, let 5 represent an armorplate, say, of the normal thickness of four nches and with its face- 6 hardened to 'the depth indicated by the dotted line in Figs.

have shown one end of such plate as of normal thickness and the other end deformed views of aplate having depressions on vI and 2. For purposes of comparison I so as to-produce thereina series of ribs 7 8,

intersectlng each other and bounding intervening pyramidal de ressions 9, the-walls of the ribs being sli htf base and the thickness of the metal through these ribs being five and one-half inches, as

y curved from apex to TOO indicated in the drawings, while the late v has a thickness in its depressed plane 0 two inches. Now assuming that the smallest sized projectile capable of penetrating a fourinch plate is of fiveinch caliber, it is obvious that the depression should fall within the cross-sectional area of such a projectile and,

conversely, that the ribs should be sodisposed that the projectile could at no point penetrate the plate without cutting through the same on one of its lines of greatest thickness, or, in other words, through one of -the ribs. The strength of the plate is due to the thickness of the metal on any line through which the projectile must pass, and therefore the metal is so disposed as to afford this increased thickness at some point wlthin the cross-sectional area of the impact spot the nieasure of efliciency of the plate is thereby determined. I prefer to provide these ribs and corresponding depressions upon one of the surfaces only; but it is feasible, of course, to form such ribs and depressions in both sides of the plates, and this construction is illustrated in Figs. 3 and 4. In this case each rib 7 is opposite a corresponding depiession on thereverse side of the plate.

'le this construction increases the comparative thickness of the plate from four to seven inches, yet it is not so desirable, as difi' ficulties would be presented in the way of hardening the face and also in the increased resistance to movement through the water if such ribbed surface were below the water.-

line. This latter objection, however, might readily be overcome by covering such ribbed plate with a skin of thin metal sheets. ribs at their outer or face plane of plate have a curved and pointed contour similar to a pointed or rounded wedge, thereby'presenting a cutting and deflecting surface to impactin projectiles.

Whi e I have shown and described two I forms of ribbing, it will be understood that my-invention is not limited to any particular form of ribor depression ncr to any particular means or apparatus for forming the same. It will be observed that the ribs are so arranged as to intersect each other, and

in both the illustrations shown the intersecting ribs are arranged at right angles to each other; but it is obvious thatthe ribs might be so arranged as to intersect each other at different angles, thereby producing depressions ofdifferent forms, and it will be understood that my invention is not limited to any particular arrangement of the ribs and.

' depressions so long as they are so arranged that the depressions are not greater in crosssection than that of a projectile which upon normal impact will be capable of penetrating a plate of the nor-ma thickness. It is readilyseen that if it require a five-inch pro- The jectile to penetrate an ordinary face-hardened armor-plate of-four inches in thickness the ribbing of said plate, whereby an additional thickness of one andone-half inches is provided, will increase the resistant efiect of the plate so-as to avoid ,penetration. This object is attained by'my' in 'vention by a redisposition of the material without increasing the weight of the plate.

I claim 1. Armor-plate provided with'arch-shaped or tapering depressions on its rear face, said plate having a hardened or chilled front face.

2. Armor-plate provided with intersecting ribs on its rear face.

3. Armor-plate provided upon one or both of\its faces with dome-shaped or arched depressions encompassed by intersecting wed ge-shaped ribs, said ribs at their outer or face plane having a curved or pointed contour similar to a pointed or rounded wedge;

4. Armor-plate having one or both of its faces indented with taperwise depressions encompassed by intersecting triangular-shaped ribs urved at their apex. I

.Armor-plate having one or both faces provided with intersecting ribs of afcurved 'triangular-sha ed cross-section.

' 6. Armor-p ate provided upon one or both of its faces with intersecting cuniform ribs having a rounded or pointed apex.

7. Armor-plate provided with surface ribs intersecting each other and bounding depressions, said ribs having a curved or pointed contour and presentin a cutting and deflecting surface at outer p ane' of plate. 4 I

8. Armor-platehafing one of its faces provided with 'cuniform ribs bounding curved I 95 ribs, and said ribs vanishing in a curved or pointed apex.

I EMIL GATHMANN.

Witnesses: '4

F. J. SASSAMAN, CHAS. B. SEEM. 

